Systems associated with fluid flow systems, and their monitoring and control, may require a power source. For example, in the oil and gas industry, throughout the lifetime of a well, it may be required to supply power to apparatus in or associated with the well. Such powered systems can include, for example, actuation systems requiring mechanical operation such as flow control devices, chokes, valves, etc., sensors such as pressure sensors, communications systems, diagnostic systems, and the like.
It may be convenient for apparatus to be powered by a local power source, such as a battery or generator forming part of apparatus introduced into a well or other fluid conduit. However, in some instances it may be impractical or impossible to supply power in this way.
In the oil and gas industry, placing of downhole components may conflict with future access requirements. For example, it may not be possible for power transmission cables to bypass packers. Apparatus may also become isolated, for example in an old branch of a multilateral well, or where topside installations are removed or abandoned.
The local environment within a fluid flow system (e.g. high temperatures) may also mitigate against the use of apparatus with local power sources such as batteries. For example, temperature of 100-150° C. or more, as routinely encountered in a well, may significantly reduce the lifetime of an electrical battery or indeed prevent its use entirely; particularly where power may be required intermittently over the course of months or years.
To address these shortcomings, it is known to generate power from fluid flowing past a turbine within a conduit, for example as described in the applicant's co-pending UK patent application no. GB 2509931.